Dynamic highlighting of geographic entities on electronic maps

ABSTRACT

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, can be used to dynamically generate electronic maps with highlighted entity boundaries. In one aspect, a method includes receiving a request for an electronic map segment for a geographic region, with the request identifying a geographic entity to be highlighted in the requested electronic map segment. A plurality of layers of map data associated with the geographic region and data defining a boundary of the identified geographic entity are retrieved in response to the request. The electronic map segment is rendered based on the retrieved plurality of layers of map data and the data defining the boundary of the geographic entity, with one or more of the retrieved layers are rendered over a rendering of a highlighted boundary of the geographic entity. The rendered electronic map segment is transmitted in response to the request.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119(e) of U.S.Patent Application No. 61/478,759, entitled “Dynamic Highlighting ofGeographic Entities on Electronic Maps,” filed Apr. 25, 2011, which isincorporated herein by reference in its entirety.

BACKGROUND

This specification relates to performing dynamic highlighting ofgeographic entities on electronic maps.

Online mapping utilities provide a convenient resource to view maps ofselected geographic areas and to navigate to different levels of detail(e.g., by zooming in or out) and to different geographic areas (e.g., bypanning). In some cases, users can select types of features (e.g.,terrain, labels, traffic) that are shown on the map. In addition, usersmay be able to place markers (e.g., waypoints) on a map, draw lines(e.g., routes) on the map, or associate photos or other information witha location on a map. Online map search tools allow users to search for alocation or a business and display a map of an area around the locationor business. In some cases, a map displayed in response to a searchrequest includes a pin or other marker that shows a location of thelocation or business that is responsive to the search request. Variousmap tools also provide mechanisms for overlaying routes (e.g., from auser-selected origination location to a user-selected destinationlocation) or other graphical information on a map.

SUMMARY

This specification describes technologies relating to dynamicallyhighlighting a boundary or extent of a geographic entity. For example,in response to a search query from a user device, a server can identifya geographic entity that is the subject of the search. Based on theidentification, data defining a boundary or extent of the geographicentity can be retrieved for use in highlighting the geographic entity ona map. A map segment that includes the geographic entity can be renderedusing map layer data and the data defining the boundary of thegeographic entity, and at least some of the map layer data can berendered over the boundary of the geographic entity.

In general, one innovative aspect of the subject matter described inthis specification can be embodied in methods that include the actionsof receiving, at a server, a request from a client device for anelectronic map segment for a geographic region, wherein the requestincludes an identification of a geographic entity to be highlighted inthe requested electronic map segment; retrieving, from one or morecontent databases, a plurality of layers of map data associated with thegeographic region in response to the request for the electronic mapsegment; retrieving, from one or more geographic entity databases, datadefining a boundary of the geographic entity in response to theidentification of a geographic entity to be highlighted in the requestedelectronic map segment; rendering the electronic map segment based onthe retrieved plurality of layers of map data and the data defining theboundary of the geographic entity, wherein one or more of the retrievedplurality of layers are rendered over a rendering of a highlightedboundary of the geographic entity; and transmitting the renderedelectronic map segment to the client device in response to the request.Other embodiments of this aspect include corresponding systems,apparatus, and computer programs, configured to perform the actions ofthe methods, encoded on computer storage devices.

These and other embodiments can each optionally include one or more ofthe following features. A search request that identifies the geographicentity is received, wherein the search request includes the request foran electronic map segment for a geographic region that includes thegeographic entity, and highlighting the geographic entity is performedbased on an inclusion of the identification of the geographic entity inthe search request. A search request that identifies the geographicentity is received, the geographic region that includes the geographicentity is identified in response to the search request, and theidentification of the geographic entity to be highlighted in therequested electronic map segment is generated in response to the searchrequest. A set of one or more search results is generated in response tothe search query, an identification of a geographic region associatedwith each search result is generated, and the set of one or more searchresults and the identification of the associated geographic region aresent to the client device. The request for the electronic map segmentfor the geographic region is received from the client device in responseto at least sending the set of one or more search results and theidentification of the associated geographic region to the client device.The request for the electronic map segment for the geographic region isreceived from the client device in further response to a selection atthe client device of a particular search result.

A first search request that identifies the geographic entity isreceived, wherein the identification of the geographic entity to behighlighted in the requested electronic map segment is based on theidentification of the geographic entity in the first search request andhighlighting the geographic entity is performed based on the inclusionof the identification of the geographic entity in the first searchrequest. A second search request relating to a geographic region thatincludes at least a portion of the geographic entity is received,wherein the second search request does not include an identification ofthe geographic entity, and a plurality of layers of map data associatedwith the geographic region that includes at least a portion of thegeographic entity in response to at least the second search request areretrieved from the one or more content databases. A second electronicmap segment is rendered based on the retrieved plurality of layers ofmap data, wherein the second electronic map segment does not include ahighlighted boundary of the geographic entity, and the rendered secondelectronic map segment is transmitted to the client device in responseto at least the second search request. The identification of ageographic entity to be highlighted in the requested electronic mapsegment is included in the request in response to a selection at theclient device of an option to include highlighting of searchedgeographic features. The data defining a boundary of the geographicentity includes data indicating an imprecise boundary, and the renderingof the highlighted boundary of the geographic entity represents a fuzzyboundary.

The rendered electronic map segment includes a plurality of map tiles,and a resource name is assigned to each of the plurality of map tiles,wherein the resource name for the map tiles that include at least aportion of the rendering of the highlighted boundary of the geographicentity distinguishes the map tile from a map tile having a correspondinggeographic scope without the highlighted boundary of the geographicentity. The plurality of the map tiles are cached, and a second requestfor an electronic map segment for the geographic region is received,wherein the second request does not include an identification of ageographic entity to be highlighted in the requested electronic mapsegment. A subset of the cached map tiles is identified, wherein thesubset includes map tiles that do not include a rendering of thehighlighted boundary of the geographic entity, map tiles that do notinclude a rendering of the highlighted boundary of the geographic entitycorresponding to the cached map tiles for the geographic region thatinclude a rendering of the highlighted boundary of the geographic entityare retrieve, and the cached map tiles in the identified subset and theretrieved map tiles are presented to provide the requested electronicmap segment. The rendering of the highlighted boundary of the geographicentity includes at least one of an outline of an area corresponding tothe geographic entity on the electronic map segment or a fill of an areacorresponding to the geographic entity on the electronic map segment.The rendering of the highlighted boundary of the geographic entityincludes an outline of edges of a road. The retrieved plurality oflayers that are rendered over a rendering of a highlighted boundary ofthe geographic entity include at least one of labels, roads, icons, orgeographic features.

In general, another aspect of the subject matter described in thisspecification can be embodied in methods that include the actions ofreceiving a request for an electronic map segment for a geographicregion, wherein the request includes an identification of a geographicentity identified based on a search request for the geographic entitysubmitted from a client device; retrieving, in response to the requestfor the electronic map segment, a plurality of layers of map dataassociated with the geographic region and data defining a boundary ofthe geographic entity; rendering the electronic map segment based on theretrieved plurality of layers of map data and the data defining theboundary of the geographic entity, wherein one or more of the retrievedplurality of layers are rendered over a rendering of a highlightedboundary of the geographic entity; and transmitting the renderedelectronic map segment in response to the request.

These and other embodiments can each optionally include one or more ofthe following features. The rendering of the highlighted boundary of thegeographic entity has a different appearance in the rendered electronicmap segment than renderings of the plurality of layers of map data. Oneor more uniform resource locators identifying the geographic region arereceived, including the identification of the geographic entity, andindicating that a boundary of the geographic entity is to behighlighted, and the one or more uniform resource locators areinterpreted to identify the geographic region, the plurality of layersof map data, and the geographic entity. The one or more uniform resourcelocators are generated in response to a search request identifying thegeographic entity. A second request for a second electronic map segmentfor a second geographic region that includes at least a portion of thegeographic entity is received, wherein the second geographic region isidentified based on a search request submitted from a client device, andin response to the second request for the second electronic map segment,a plurality of layers of map data associated with the geographic regionare retrieved. The second electronic map segment is rendered based onthe retrieved plurality of layers of map data without rendering ahighlighted boundary of the geographic entity, and the rendered secondelectronic map segment is transmitted in response to the second request.The geographic entity includes a first geographic entity, and a secondrequest for a second electronic map segment for a second geographicregion that includes at least a portion of the first geographic entityis received, wherein the second request includes an identification of asecond geographic entity identified based on a search request for thesecond geographic entity submitted from a client device. In response tothe second request for the second electronic map segment, a plurality oflayers of map data associated with the second geographic region and datadefining a boundary of the second geographic entity are retrieved. Thesecond electronic map segment is rendered based on the retrievedplurality of layers of map data and the data defining the boundary ofthe second geographic entity, wherein one or more of the retrievedplurality of layers are rendered over a rendering of a highlightedboundary of the second geographic entity without rendering a highlightedboundary of the first geographic entity, and the rendered secondelectronic map segment is transmitted in response to the second request.The rendering of the highlighted boundary of the geographic entityrepresents a fuzzy boundary for the geographic entity.

In general, another aspect of the subject matter described in thisspecification can be embodied in systems that include one or more maprequest interpretation servers, one or more map rendering servers, andone or more map front end servers. The one or more map requestinterpretation servers are adapted to receive a map request for anelectronic map segment for a geographic region, wherein the map requestincludes an identification of a geographic entity identified based on asearch request related to the geographic entity submitted from a userdevice, and request retrieval, in response to the map request for theelectronic map segment, a plurality of layers of map data associatedwith the geographic region and data defining a boundary of thegeographic entity. The one or more map rendering servers are adapted torender the electronic map segment based on the retrieved plurality oflayers of map data and the boundary of the geographic entity, whereinone or more of the retrieved plurality of layers are rendered over arendering of a highlighted boundary of the geographic entity. The one ormore map front end servers are adapted to transmit the renderedelectronic map segment in response to the map request.

These and other embodiments can each optionally include one or more ofthe following features. The system can include one or more map searchservers adapted to receive the search request for the geographic entitysubmitted from a user device, identify a geographic region associatedwith the geographic entity in response to the search request, andgenerate the identification of the geographic entity in response to thesearch request. The one or more map search servers are further adaptedto generate a uniform resource locator including the identification ofthe geographic region and the identification of the geographic entity. Auser device is adapted to display the rendered electronic map segment.The user device is further adapted to transmit the map request to themap request interpretation server in response to receiving the uniformresource locator. The user device is further adapted to initiate thesearch request.

Particular embodiments of the subject matter described in thisspecification can be implemented so as to realize one or more of thefollowing advantages. The boundary or extent of a particular geographicentity can be displayed on a user interface. Users may be able toreadily determine, for example, whether a particular location fallswithin the boundary of a specific geographic entity or the size andshape of a particular geographic entity. The boundary can be displayedin response to a search request that identifies or relates to thegeographic entity and/or can be displayed in a manner that distinguishesthe appearance of the boundary from other features displayed on anelectronic map. An electronic map that includes the boundary can berendered dynamically, and the highlighting of the boundary can berendered so that it does not obscure other features (e.g., labels,streets, important geographic features, or icons) included on a map.Maps or map tiles that include highlighted boundaries can use resourcenames (e.g., uniform resource identifiers) that indicate that the map ormap tile includes highlighting and/or an identification of the entitythat is highlighted, which can facilitate re-use of the map or map tile(e.g., from a cache) if highlighting is desired or can help indicatethat a non-highlighted version of the map or map tile needs to beretrieved or generated if the same highlighting is not desired.Different styles of highlighting can be used depending on whether theboundaries are concrete or are less definitive. Different styles canalso be applied according to the particular context (e.g., thickerhighlighting can be used when a map is zoomed out so that relativelocation to other entities is easier to recognize, paler highlightingcan be used when map is zoomed in so that highlighting does notinterfere with map details, changing layer levels to place thehighlighting so it less interfering, or using different style fordifferent map styles).

The details of one or more embodiments of the subject matter describedin this specification are set forth in the accompanying drawings and thedescription below. Other features, aspects, and advantages of thesubject matter will become apparent from the description, the drawings,and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an electronic map generation system.

FIG. 2 is a conceptual diagram of a process for rendering map layers andboundary highlighting to generate an electronic map segment.

FIGS. 3A-3E illustrate an example of a rendering sequence for anelectronic map.

FIG. 4 is an illustrative example of a highlighted boundary for ageographic entity in a more detailed electronic map segment.

FIG. 5 is another illustrative example of a highlighted boundary for ageographic entity in a more detailed electronic map segment.

FIG. 6 is a flow diagram of a process for dynamically generating anelectronic map segment with a highlighted boundary.

FIG. 7 is a flow diagram of a process for using both map segments thatinclude highlighted boundaries and map segments that do not includehighlighted boundaries.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

FIG. 1 is a block diagram of an electronic map generation system 100.The system 100 can be used for dynamically generating highlightedboundaries on a dynamically generated electronic map segment. The system100 includes user devices 102, a search system 110, and a map generationserver 120. The user devices 102 are capable of communicating over anetwork 104 (e.g., the Internet or other wide area network, a local areanetwork, a cellular network, any other network capable of carryingelectronic data, or any combination thereof) with the search system 110to initiate search queries and receive search results. In addition, theuser devices 102 can also communicate over the network 104 with the mapgeneration server 120 to request and receive electronic map segments. Insome embodiments, the search system 110 and the map generation server120 can be implemented in the same physical servers, although theactions performed by the search system 110 and the map generation server120 may be performed by different modules and/or different virtualmachines. Moreover, although the map generation server 120 is depictedas a single server, the map generation server 120 may be implementedacross multiple servers in a server farm or across multiple server farmsthat cooperate to perform the operations of the map generation server120.

Generally, electronic maps are not retrieved in their entirety, at leastnot when the available electronic map includes a large amount of detailand/or covers a large geographic area that can be viewed at varying zoomlevels. Rather, electronic maps are generated in segments according toparameters provided by the user devices and/or the search system 110. Anelectronic map segment may include multiple electronic map tiles, witheach map tile being rendered independently of neighboring tiles, and thesize and zoom level of the map segment may be selected based on the sizeof the geographic entity (e.g., neighborhood, city, state), the size orshape of the display on which the electronic map segment is to bedisplayed, and/or other parameters (e.g., a desired number of initiallyhidden map tiles to be provided in case the user pans or zooms). The maptiles can be embodied in electronic documents. An electronic document(which for brevity will simply be referred to as a document) may, butneed not, correspond to a file. A document may be stored in a portion ofa file that holds other documents, in a single file dedicated to thedocument in question, or in multiple coordinated files.

The user devices 102 can include, for example, personal computers 102 aand 102 b, personal digital assistants 102 c, mobile phones 102 d, orother types of devices (e.g., tablet computers) capable of communicatingover a network 104 and displaying electronic maps to a user. Generally,the user devices 102 include a display 130, a processor 132, a memory134, and a user input interface 136. Users can enter search queries orother parameters using the user input interface 136 to initiateretrieval of search results or electronic map segments. For example, theuser input interface 136 may be used to type a search query into asearch field in a web page displayed on the display 130. The web pagemay be stored in the memory 134 and displayed on the display 130 inaccordance with instructions executed by the processor 132. The memory134 may also store instructions that, when executed by the processor132, cause the user device 102 to transmit search requests to the searchsystem 110, display received search results, request electronic mapsegments (e.g., based on user input or on data received from the searchsystem 110), and display received electronic map segments. In somecases, the user device 102 can automatically request (e.g., usingscripts or other instructions) electronic map tiles identified in asearch result returned by the search system 110.

The memory 134 may also store cached electronic map tiles. Scripts(e.g., JavaScript®) or other instructions can be used to manage thecache such that received electronic map tiles are stored in the cache(e.g., during a session, for some other predetermined period of time, oruntil the cache reaches a size threshold) and can be retrieved from thecache rather than requesting them from the map generation server 120(e.g., when a user pans away from an area and then pans back to the samearea). The search system 110 and/or the map generation server 120 canassign unique uniform resource locators (URLs) to the map tiles. TheURLs can be used by the user device 102 to identify, to the mapgeneration server 120, specific map tiles that are needed. The URLs canalso be used to catalog map tiles that are stored in the cache such thatwhen a particular map tile is needed, the user device 102 can firstcheck the local cache to determine if the map tiles has already beenretrieved. If so, the local copy of the map tile can be used. If not,the user device 102 can request the map tile from the map generationserver 120. In some implementations, map tiles may similarly be cachedat the server level so that frequently used map tiles need not berepeatedly generated by the map generation server 120.

The search system 110 can receive search requests from user devices 102at a search engine front end 112. The search system 110 can beimplemented across a large number of modules and/or servers, which mayfurther be geographically distributed in multiple server farms. In someembodiments, the search system 110 may be designed to handle numerousdifferent types of search requests (e.g., general web searches and mapsearches) although such search requests may be submitted using differentweb pages or web interfaces. In such embodiments, the search enginefront end 112 may be responsible for routing the search request to theappropriate modules or servers according to the type of search request.In other embodiments, the search system may be focused on a particulartype of search request (e.g., a map search), and the search engine frontend 112 may perform pre-processing (e.g., separating the search requestinto component parts or re-sequencing or normalizing the search request)and/or determine how to route the request or component parts of therequest.

The search system 110 may determine if a received search request is fora specific location or entity using location data stored in one or moreentity databases 140. For example, the received search query may becompared against known entities to identify one or more possibleentities responsive to the search query. Although the search system 110may be capable of identifying virtual entities (e.g., web sites orbusinesses independent of their physical location or locations), theentity databases are generally used in support of the techniquesdescribed in this specification to identify physical locations ofentities. In some cases, the search system 110 may identify a virtualentity and then determine if the virtual entity has a correspondingphysical presence (e.g., near a user's current location if the userpermits location data to be provided to the search system 110, or near alocation of a map currently displayed on the user device 102 when theuser submits the search query).

The search system 110 includes a search result generation module 114,which again may be implemented across a large number of servers. If oneor more entities are identified as being responsive to the search query,the search result generation module 114 can retrieve data from ageographic entity database 145 that provides data about the entity at aparticular location. The geographic entity data can include, forexample, data indicating a physical location of the entity (e.g., anapproximate center of the entity), a physical size of the entity (e.g.,how far the outer boundaries of the entity are from the entity center),a preferred map segment and zoom level to display for the entity, and/ora URL or other identifier associated with a preferred map segment forthe entity. In some cases, the search result generation module 114 maygenerate an appropriate URL based, for example, on the location of theentity and physical size of the entity, or the URL can be dynamicallygenerated by client module (e.g., using JavaScript®) based oninformation returned by the search result generation module 114 and/orthe user's behavior (e.g., pan, zoom, etc). The URL can include anidentification of the entity and an indication that the boundary of theentity is to be highlighted in an electronic map segment provided inresponse to the search query or in response to a selection of a searchresult for the search query. Moreover, the URL may be generated based onthe type of map (e.g., plain map, terrain map, satellite map, orcombination) to be provided and on user-selected options for features tobe included on the map segment. Thus, the URL can include data that canbe parsed and interpreted to dynamically generate an electronic mapsegment that includes features desired by the user and that includeshighlighting of the border of the particular geographic entity. Theinclusion of data indicating that such border highlighting should beincluded can be based on the nature of the search request (e.g., asearch request for the specific entity to be highlighted) and/or onuser-selected preferences that indicate whether entity highlighting isdesired. The search result generation module 114 can also perform otheroperations, e.g., generating a web page that includes a list of thesearch results.

Once the search results generation module 114 has generated one or moresearch results, the search system 110 transmits the search result orresults to the user device 102. In some cases, the search result can bea single geographic entity (e.g., for a map search with a highconfidence level in a particular result) or the set of search resultscan be limited to a single map result (e.g., for a general search thathas a relatively high likelihood of being an entity location search). Inother cases, the search results can include multiple geographicentities, each of which may have a different associated URL for use inretrieving a highlighted map segment.

After receiving the search result or results, the user device 102 canautomatically send a request (e.g., using a script incorporated in thesearch results web page) to the map generation server 120 to retrievethe electronic map segment. Alternatively, retrieval of the map segmentmay be initiated upon selection of a particular search result by theuser. As another alternative, a thumbnail or other small map segment maybe requested automatically for one or more search results, and, if theuser selects the thumbnail or small map segment or a link associatedwith the corresponding search result, a larger electronic map segmentcan be retrieved. In yet another alternative embodiment, an electronicmap segment can be retrieved prior to sending the search result orresults to the user device 102. In such a case, the search system 110can interact directly with the map generation server 120 and the searchresult or results can include the electronic map segment. While such atechnique may simplify the operations (e.g., scripting) performed at theuser device 102, it can also introduce delay in sending results to theuser device 102.

The map generation server 120 receives requests to generate anelectronic map segment at a map front end module 122, which may handlereceiving map requests and sending responsive maps to the requestinguser device 102. The map front end module 122 can pass the request alongto a map request interpretation module 124. The map requestinterpretation module 124 can parse the request (e.g., by separating outdifferent fields in a received URL that identifies the requested mapsegment or a received plurality of URLs that describe the requested maptiles that make up the map segment) and can interpret the parsedinformation to determine what map data is needed to generate therequested map segment. For example, the map request interpretationmodule 124 can determine the type of base map data is needed (e.g.,plain map, terrain, and/or satellite imagery), the general location andzoom level within the universe of available map data (e.g., byidentifying particular tiles, an area between or including specificgeographic coordinates, a center point and zoom level, etc.), map layersneeded, whether highlighting is to be applied, and/or the entity to behighlighted. The identification of map data can be passed to a maplayering module 126, which retrieves the appropriate map layer data fromone or more map layer databases 150. For example, the map layerdatabases 150 can store data including base map data, roads, terrain,geographic features, municipalities, labels, icons, satellite imagery,traffic data, photos, user-generated content, etc. The map layeringmodule 126 can also retrieve data defining the boundary of thegeographic entity to be highlighted from a boundary database 155, whichcan store, for example, polygon and/or polyline informationcorresponding to various geographic entities (e.g., city, county, orother administrative division; street; school district; neighborhood;province; state; zip code area; building; campus; etc.). In someinstances, the boundary data can include multiple segments and/or candefine multiple non-contiguous areas (e.g., for a campus, municipality,or country that includes non-contiguous physical locations). Theboundary data can also include data indicating that some or all of theboundary is imprecise (e.g., for a neighborhood) and/or a degree ofimprecision.

The map layer data and boundary data are used by a map rendering module128 to generate the requested electronic map segment. In someimplementations, the layers can be rendered in a relative sequence toprevent information in certain layers (e.g., labels or roadways) frombeing obscured. Thus, the boundary highlighting can be rendered behindother layers. Rendering in a relative sequence need can be done eithertemporally (e.g., by rendering each layer on top of the prior layer in aspecific sequence) or in a relative positional sequence without regardfor the temporal sequence (e.g., by selectively rendering certain layersbehind or in front of other layers). The requested electronic mapsegment can thus be dynamically rendered to provide selective boundaryhighlighting of a geographic entity that was the subject of a searchrequest or that is otherwise identified as being of particular interestfor display to the user. The boundary highlighting can include any typeof visual features (e.g., solid, dashed, and/or colored boundary lines,semi-transparent fill or shading, fill patterns, etc.) that tends todistinguish the boundaries and/or extent of the geographic entity fromother parts of the map segment. Boundary highlighting for impreciseboundaries can use fuzzy boundaries (e.g., boundaries that do notinclude distinct edges or that gradually fade in a particulardirection). In addition, data indicating the degree of imprecision for aboundary can be used to modify the fuzziness of the boundary (e.g., howquickly the boundary fades).

The rendered electronic map segment can then be transmitted back to therequesting user device 102 by the map front end module 122 forpresentation on a display 130 of the user device 102. In someimplementations the map front end module 122, the map requestinterpretation module 124, the map layering module 126, and the maprendering module 128 can be implemented in different servers and/or in avirtual computing environment.

FIG. 2 is a conceptual diagram of a process 200 for rendering map layersand boundary highlighting to generate an electronic map segment 230. Inthis illustrative example, map layers including base map data 202,shading (or color) data 204, boundary data 206, street data 208, and maplabel data 210 are provided to a rendering engine 220, which renders thevarious layers in a particular positional sequence (e.g., to preventinformation, graphics, or images in certain layers from obscuringinformation, graphics, or images in other layers). The positionalsequence can be predetermined but can also vary depending on the type ofmap, user preferences, user selections, and/or the combination of layersthat are included in a particular map segment. The rendering engine 220outputs an electronic map segment 230 that can include boundaryhighlighting generated in a manner such that the map is customizedaccording to the particular search query submitted by the user. In otherwords, different map segments (i.e., with different highlightedgeographic entities) can be generated for a particular geographic areadynamically.

FIGS. 3A-3E illustrate an example of a rendering sequence for anelectronic map 300. The rendering sequence is intended for illustrativepurposes and does not include full map details. Moreover, differenttemporal sequences of rendering the map layers can be used to achievethe same end result (e.g., relative positional sequence of the maplayers). FIG. 3A depicts an illustrative example of a base map layer 302that includes a shoreline 320, park boundaries 322, and lake boundaries324. FIG. 3B depicts an illustrative example of a map shading layer 304overlaying the base map layer 302. The map shading layer 304 includesfirst shading or coloring 330 for parks and second shading or coloring332 for lakes. The map shading layer 304 can also include additionalshading or coloring for other land areas 334 and surrounding water 336,although such shading or coloring is not shown in FIG. 3B forconvenience. FIG. 3C depicts an illustrative example of an entityboundary layer 306 overlaying the map shading layer 304. The entityboundary layer 306 includes a highlighted boundary 340 for a selectedgeographic entity (e.g., a neighborhood, such as the so-called SoMa orSouth of Market neighborhood in San Francisco). FIG. 3D depicts anillustrative example of a roads layer 308 overlaying the entity boundarylayer 306. The roads layer 308 includes various major roadways 350.Although only a few roadways are shown for convenience, a typical map ata city zoom level may include numerous roads. In this example, the roadspartially obscure the geographic entity boundary 340, although in someimplementations, the boundary 340 can be depicted such that the locationof the boundary can still be determined despite the partial obstruction(e.g., using a semi-transparent fill or using boundary lines that areadjacent to the potentially obscuring roadway graphics). FIG. 3E depictsan illustrative example of a labels layer 310 overlaying the roads layer308. The labels layer 308 includes roadway labels 360 and geographiclocation labels 362 that further partially obscure graphics inunderlying layers, including the geographic entity boundary 340.

FIG. 4 is an illustrative example of a highlighted boundary 405 for ageographic entity in a more detailed electronic map segment 400. In thisexample, the highlighted boundary 405 includes a colored outline and asemi-transparent fill, both of which differentiate the extent of theselected geographic entity (i.e., Switzerland) from other areas shown onthe map segment without obscuring at least the geographic labels on themap segment.

FIG. 5 is another illustrative example of a highlighted boundary 505 fora geographic entity in a more detailed electronic map segment 500. Inthis example, the highlighted boundary 505 indicates the extent of aroad (i.e., the entire length of a particular roadway, e.g., before itchanges to a different name, dead-ends, or meets another roadway). Thehighlighted boundary 505 includes a colored outline that differentiatesthe extent of the selected geographic entity (i.e., Homestead Road) fromother roads and areas shown on the map segment. Again, the highlightedboundary 505 does not obscure either the graphics for the roadway itselfor the associated labels.

FIG. 6 is a flow diagram of a process 600 for dynamically generating anelectronic map segment with a highlighted boundary. The process 600includes receiving a search request that relates to a geographic entityat 602. The search request can be determined to relate to the geographicentity based on including the entity name or a shorthand version of theentity name and/or based on a likelihood that the geographic entity iswhat is intended (e.g., based on the general location from which thesearch request originates and/or based on relative popularity of similarnamed places). The search request can be interpreted as being,implicitly, a request for an electronic map segment that includes thegeographic entity based on the type of search web page used to submitthe search request (e.g., a search within a map search field can beimplicitly interpreted as a request to retrieve the map). Alternatively,the search request (e.g., in a general web search web page) can beinterpreted such that one possible result is an electronic map of thegeographic entity.

One or more search results are generated at 604 in response to thesearch query, at least one of which includes the geographic entity. Ageneral geographic region or area that includes the geographic entity isidentified at 606. The identification of the region or area can be basedon a central location within the geographic entity and on an extent towhich the entity expands from the central location. Based on theidentified general geographic region or area, parameters defining a mapsegment to be retrieved can be determined at 608. The parameters candefine, for example, a plurality of map tiles needed to cover the regionor area, an appropriate zoom level for a map that displays thegeographic entity (e.g., such that all or most of the full extent of theentity is included within a displayed map segment), and/or geographiccoordinates for the outer edges of the desired map segment.

A request for an electronic map segment is generated and sent at 610.The request includes an indication that the requested map segment is toinclude boundary highlighting and an identification of the geographicentity to be highlighted in the requested map segment. For example, suchinformation can be included along with the parameters defining the mapsegment in the form of one or more resource identifiers (e.g., URLs).Multiple layers of map data associated with the identified region orarea and with the requested map segment are retrieved at 612. Forexample, the map data layers that are needed can be determined based onthe parameters included in the request to generate a map segment. Datadefining a boundary of the identified geographic entity is alsoretrieved at 614. The electronic map segment is rendered at 616 usingthe retrieved map data layers and the geographic entity boundary data.In addition, the rendering can be performed such that one or more of theretrieved layers (e.g., labels, roads, icons, and/or geographicfeatures) are rendered over the rendering of the highlighted boundaryfor the geographic entity. The rendered map segment can then betransmitted (e.g., to a requesting user device) in response to theelectronic map segment request at 618.

FIG. 7 is a flow diagram of a process 700 for using both map segmentsthat include highlighted boundaries and map segments that do not includehighlighted boundaries. The process 700 includes receiving a pluralityof map tiles at 702 and caching the map tiles at 704. The plurality ofmap tiles can include some map tiles that include boundary highlightingand other map tiles that do not include boundary highlighting (e.g.,areas of the map segment that do not include any of the geographicentity having a highlighted boundary). Subsequently, at 706, a requestfor a new map segment that includes at least some overlap with theplurality of map tiles cached at 704 is received. The request does notinclude an indication that the same geographic entity is to behighlighted. For example, the request can indicate that a differentgeographic entity should be highlighted or that no highlighting shouldbe included.

Based on the request, one or more map tiles in the cache are identifiedat 708 for use in rendering the new map segment. For example, the maptiles that can be reused may be identified based on a match betweenresource identifiers for map tiles included in the request and resourceidentifiers for map tiles stored in the cache. In addition, one or moremap tiles that need to be generated are identified at 710. For example,although the cache may include map tiles that cover the same area, thecached map tiles may include highlighted boundaries that are not desiredin the new map segment. The need for generating the map tiles, despitecovering the same area as some of the cached map tiles, can beidentified based on differences in the resource identifiers betweenresource identifiers for map tiles included in the request (e.g.,indicating no highlighting or highlighting of a different entity) andresource identifiers for map tiles stored in the cache (e.g., indicatinghighlighting of the original entity). A request to generate the new maptiles can be sent at 712, and the dynamically generated map tiles can bereceived in response at 714. The newly generated map tiles and theselected cached map tiles can then be presented on a display at 716 inresponse to the request.

Embodiments of the subject matter and the operations described in thisspecification can be implemented in digital electronic circuitry, or incomputer software, firmware, or hardware, including the structuresdisclosed in this specification and their structural equivalents, or incombinations of one or more of them. Embodiments of the subject matterdescribed in this specification can be implemented as one or morecomputer programs, i.e., one or more modules of computer programinstructions, encoded on computer storage medium for execution by, or tocontrol the operation of, data processing apparatus. Alternatively or inaddition, the program instructions can be encoded on anartificially-generated propagated signal, e.g., a machine-generatedelectrical, optical, or electromagnetic signal, that is generated toencode information for transmission to suitable receiver apparatus forexecution by a data processing apparatus. A computer storage medium canbe, or be included in, a computer-readable storage device, acomputer-readable storage substrate, a random or serial access memoryarray or device, or a combination of one or more of them. Moreover,while a computer storage medium is not a propagated signal, a computerstorage medium can be a source or destination of computer programinstructions encoded in an artificially-generated propagated signal. Thecomputer storage medium can also be, or be included in, one or moreseparate physical components or media (e.g., multiple CDs, disks, orother storage devices).

The operations described in this specification can be implemented asoperations performed by a data processing apparatus on data stored onone or more computer-readable storage devices or received from othersources.

The term “data processing apparatus” encompasses all kinds of apparatus,devices, and machines for processing data, including by way of example aprogrammable processor, a computer, a system on a chip, or multipleones, or combinations, of the foregoing The apparatus can includespecial purpose logic circuitry, e.g., an FPGA (field programmable gatearray) or an ASIC (application-specific integrated circuit). Theapparatus can also include, in addition to hardware, code that createsan execution environment for the computer program in question, e.g.,code that constitutes processor firmware, a protocol stack, a databasemanagement system, an operating system, a cross-platform runtimeenvironment, a virtual machine, or a combination of one or more of them.The apparatus and execution environment can realize various differentcomputing model infrastructures, such as web services, distributedcomputing and grid computing infrastructures.

A computer program (also known as a program, software, softwareapplication, script, or code) can be written in any form of programminglanguage, including compiled or interpreted languages, declarative orprocedural languages, and it can be deployed in any form, including as astand-alone program or as a module, component, subroutine, object, orother unit suitable for use in a computing environment. A computerprogram may, but need not, correspond to a file in a file system. Aprogram can be stored in a portion of a file that holds other programsor data (e.g., one or more scripts stored in a markup languagedocument), in a single file dedicated to the program in question, or inmultiple coordinated files (e.g., files that store one or more modules,sub-programs, or portions of code). A computer program can be deployedto be executed on one computer or on multiple computers that are locatedat one site or distributed across multiple sites and interconnected by acommunication network.

The processes and logic flows described in this specification can beperformed by one or more programmable processors executing one or morecomputer programs to perform actions by operating on input data andgenerating output. The processes and logic flows can also be performedby, and apparatus can also be implemented as, special purpose logiccircuitry, e.g., an FPGA (field programmable gate array) or an ASIC(application-specific integrated circuit).

Processors suitable for the execution of a computer program include, byway of example, both general and special purpose microprocessors, andany one or more processors of any kind of digital computer. Generally, aprocessor will receive instructions and data from a read-only memory ora random access memory or both. The essential elements of a computer area processor for performing actions in accordance with instructions andone or more memory devices for storing instructions and data. Generally,a computer will also include, or be operatively coupled to receive datafrom or transfer data to, or both, one or more mass storage devices forstoring data, e.g., magnetic, magneto-optical disks, or optical disks.However, a computer need not have such devices. Moreover, a computer canbe embedded in another device, e.g., a mobile telephone, a personaldigital assistant (PDA), a mobile audio or video player, a game console,a Global Positioning System (GPS) receiver, or a portable storage device(e.g., a universal serial bus (USB) flash drive), to name just a few.Devices suitable for storing computer program instructions and datainclude all forms of non-volatile memory, media and memory devices,including by way of example semiconductor memory devices, e.g., EPROM,EEPROM, and flash memory devices; magnetic disks, e.g., internal harddisks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROMdisks. The processor and the memory can be supplemented by, orincorporated in, special purpose logic circuitry.

To provide for interaction with a user, embodiments of the subjectmatter described in this specification can be implemented on a computerhaving a display device, e.g., a CRT (cathode ray tube) or LCD (liquidcrystal display) monitor, for displaying information to the user and akeyboard and a pointing device, e.g., a mouse or a trackball, by whichthe user can provide input to the computer. Other kinds of devices canbe used to provide for interaction with a user as well; for example,feedback provided to the user can be any form of sensory feedback, e.g.,visual feedback, auditory feedback, or tactile feedback; and input fromthe user can be received in any form, including acoustic, speech, ortactile input. In addition, a computer can interact with a user bysending documents to and receiving documents from a device that is usedby the user; for example, by sending web pages to a web browser on auser's client device in response to requests received from the webbrowser.

Embodiments of the subject matter described in this specification can beimplemented in a computing system that includes a back-end component,e.g., as a data server, or that includes a middleware component, e.g.,an application server, or that includes a front-end component, e.g., aclient computer having a graphical user interface or a Web browserthrough which a user can interact with an implementation of the subjectmatter described in this specification, or any combination of one ormore such back-end, middleware, or front-end components. The componentsof the system can be interconnected by any form or medium of digitaldata communication, e.g., a communication network. Examples ofcommunication networks include a local area network (“LAN”) and a widearea network (“WAN”), an inter-network (e.g., the Internet), andpeer-to-peer networks (e.g., ad hoc peer-to-peer networks).

The computing system can include clients and servers. A client andserver are generally remote from each other and typically interactthrough a communication network. The relationship of client and serverarises by virtue of computer programs running on the respectivecomputers and having a client-server relationship to each other. In someembodiments, a server transmits data (e.g., an HTML page) to a clientdevice (e.g., for purposes of displaying data to and receiving userinput from a user interacting with the client device). Data generated atthe client device (e.g., a result of the user interaction) can bereceived from the client device at the server.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anyinventions or of what may be claimed, but rather as descriptions offeatures specific to particular embodiments of particular inventions.Certain features that are described in this specification in the contextof separate embodiments can also be implemented in combination in asingle embodiment. Conversely, various features that are described inthe context of a single embodiment can also be implemented in multipleembodiments separately or in any suitable subcombination. Moreover,although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processingmay be advantageous. Moreover, the separation of various systemcomponents in the embodiments described above should not be understoodas requiring such separation in all embodiments, and it should beunderstood that the described program components and systems cangenerally be integrated together in a single software product orpackaged into multiple software products.

Thus, particular embodiments of the subject matter have been described.Other embodiments are within the scope of the following claims. In somecases, the actions recited in the claims can be performed in a differentorder and still achieve desirable results. In addition, the processesdepicted in the accompanying figures do not necessarily require theparticular order shown, or sequential order, to achieve desirableresults. In certain implementations, multitasking and parallelprocessing may be advantageous. Servers may provide geographicinformation (polygon, polyline, label location and text) to a clientdevice, and map rendering may be performed on the client device.Alternatively, geographic information can be stored in local storage,such as CD/DVD-ROM, hard disk drive, or USB drive, and informationretrieval, processing, and map rendering can be done on the clientdevice, in which case no network connection is required. The maprendering module may return multiple layer images to client device,where those images are overlaid to obtain a final map image withhighlighted boundaries.

What is claimed is:
 1. A method performed by data processing apparatus,the method comprising: receiving, by one or more processors and from aclient device, a request for an electronic map segment for a geographicregion, wherein the request includes an identification of a geographicentity to be highlighted in the requested electronic map segment; inresponse to receiving the request, retrieving, by one or moreprocessors, a map data associated with the geographic region;determining whether the request includes an identification of ageographic entity to be highlighted in the requested electronic mapsegment; in response to determining that the request includes anidentification of a geographic entity to be highlighted in the requestedelectronic map segment, retrieving, by one or more processors, datadefining a geographic boundary of the geographic entity, wherein theelectronic map segment comprises a plurality of map tiles, and wherein afirst subset of the map tiles include at least part of the geographicentity to be highlighted and a second subset of the map tiles do notinclude the geographic entity to be highlighted, at least some of thesecond subset of map tiles being rendered before receiving the requestfrom the client device; rendering, by one or more processors, the firstsubset of the map tiles based on the retrieved map data and the datadefining the geographic boundary of the geographic entity, wherein thefirst subset of the map tiles comprises a rendering of a highlighting ofthe geographic boundary of the geographic entity identified by therequest; and transmitting the first subset of the map tiles andinstructions to display the electronic map segment to the client device.2. The method of claim 1 further comprising receiving a search requestthat identifies the geographic entity, wherein: the search requestcomprises the request for an electronic map segment for a geographicregion that includes the geographic entity; and highlighting thegeographic entity is performed based on an inclusion of theidentification of the geographic entity in the search request.
 3. Themethod of claim 1 further comprising: receiving a search request thatidentifies the geographic entity; identifying the geographic region thatincludes the geographic entity in response to the search request; andwherein the identification of the geographic entity to be highlighted inthe requested electronic map segment is generated in response to thesearch request.
 4. The method of claim 3 further comprising: generatinga set of one or more search results in response to the search query;generating an identification of a geographic region associated with eachsearch result; and sending the set of one or more search results and theidentification of the associated geographic region to the client device,wherein the request for the electronic map segment for the geographicregion is received from the client device in response to at leastsending the set of one or more search results and the identification ofthe associated geographic region to the client device.
 5. The method ofclaim 4 wherein the request for the electronic map segment for thegeographic region is received from the client device in further responseto a selection at the client device of a particular search result. 6.The method of claim 1 further comprising: receiving a first searchrequest that identifies the geographic entity, wherein: theidentification of the geographic entity to be highlighted in therequested electronic map segment is based on the identification of thegeographic entity in the first search request; and highlighting thegeographic entity is performed based on the inclusion of theidentification of the geographic entity in the first search request;receiving a second search request relating to a geographic region thatincludes at least a portion of the geographic entity, wherein the secondsearch request does not include an identification of the geographicentity; retrieving, from the one or more content databases, a pluralityof layers of map data associated with the geographic region thatincludes at least a portion of the geographic entity in response to atleast the second search request; rendering a second electronic mapsegment based on the retrieved plurality of layers of map data, whereinthe second electronic map segment does not include a highlightedboundary of the geographic entity; and transmitting the rendered secondelectronic map segment to the client device in response to at least thesecond search request.
 7. The method of claim 1 wherein theidentification of a geographic entity to be highlighted in the requestedelectronic map segment is included in the request in response to aselection at the client device of an option to include highlighting ofsearched geographic features.
 8. The method of claim 1 wherein at leastsome of the second subset of map tiles are stored in cache memory of theclient device before receiving the request from the client device. 9.The method of claim 1 wherein the rendered electronic map segmentincludes a plurality of map tiles, the method further comprising:assigning a resource name to each of the plurality of map tiles, whereinthe resource name for the map tiles that include at least a portion ofthe rendering of the highlighted boundary of the geographic entitydistinguishes the map tile from a map tile having a correspondinggeographic scope without the highlighted boundary of the geographicentity; caching the plurality of the map tiles; receiving a secondrequest for an electronic map segment for the geographic region, whereinthe second request does not include an identification of a geographicentity to be highlighted in the requested electronic map segment;identifying at least some of the second subset of the cached map tiles,wherein the subset includes map tiles that do not include a rendering ofthe highlighted boundary of the geographic entity; retrieving map tilesthat do not include a rendering of the highlighted boundary of thegeographic entity corresponding to the cached map tiles for thegeographic region that include a rendering of the highlighted boundaryof the geographic entity; and presenting the cached map tiles in theidentified subset and the retrieved map tiles to provide the requestedelectronic map segment.
 10. The method of claim 1 wherein the renderingof the highlighted boundary of the geographic entity includes at leastone of an outline of an area corresponding to the geographic entity onthe electronic map segment or a fill of an area corresponding to thegeographic entity on the electronic map segment.
 11. The method of claim1 wherein the rendering of the highlighted boundary of the geographicentity includes an outline of edges of a road.
 12. The method of claim 1wherein the retrieved plurality of layers comprise at least one oflabels, roads, icons, or geographic features.
 13. A computer storagemedium encoded with a computer program, the program comprisinginstructions that when executed by data processing apparatus cause thedata processing apparatus to perform operations including: receiving arequest for an electronic map segment for a geographic region, whereinthe request includes an identification of a geographic entity to behighlighted in the requested electronic map segment; in response toreceiving the request, retrieving a plurality of layers of map dataassociated with the geographic region; determining whether the requestincludes an identification of a geographic entity to be highlighted inthe requested electronic map segment; in response to determining thatthe request includes an identification of a geographic entity to behighlighted in the requested electronic map segment, retrieving datadefining a geographic boundary of the geographic entity, wherein theelectronic map segment comprises a plurality of map tiles, and wherein afirst subset of the map tiles include at least part of the geographicentity to be highlighted and a second subset of the map tiles do notinclude the geographic entity to be highlighted, at least some of thesecond subset of map tiles being rendered before receiving the requestfrom the client device; rendering the first subset of the map tilesbased on the retrieved plurality of layers of map data and the datadefining the geographic boundary of the geographic entity, wherein thefirst subset of the map tiles rendered comprises a rendering of ahighlighting of the geographic boundary of the geographic entityidentified by the request; and transmitting the rendered first subset ofthe map tiles.
 14. The computer storage medium of claim 13 wherein therendering of the highlighted boundary of the geographic entity has adifferent appearance in the rendered electronic map segment thanrenderings of the plurality of layers of map data.
 15. The computerstorage medium of claim 13 wherein the program further comprisesinstructions that when executed by data processing apparatus cause thedata processing apparatus to perform operations including: receiving oneor more uniform resource locators identifying the geographic region,including the identification of the geographic entity, and indicatingthat a boundary of the geographic entity is to be highlighted; andinterpreting the one or more uniform resource locators to identify thegeographic region, the plurality of layers of map data, and thegeographic entity.
 16. The computer storage medium of claim 15 whereinthe one or more uniform resource locators are generated in response to asearch request identifying the geographic entity.
 17. The computerstorage medium of claim 13 wherein the program further comprisesinstructions that when executed by data processing apparatus cause thedata processing apparatus to perform operations including: receiving asecond request for a second electronic map segment for a secondgeographic region that includes at least a portion of the geographicentity, wherein the second geographic region is identified based on asearch request submitted from a client device; retrieving, in responseto the second request for the second electronic map segment, a pluralityof layers of map data associated with the geographic region; renderingthe second electronic map segment based on the retrieved plurality oflayers of map data without rendering a highlighted boundary of thegeographic entity; and transmitting the rendered second electronic mapsegment in response to the second request.
 18. The computer storagemedium of claim 13 wherein the geographic entity comprises a firstgeographic entity and the program further comprises instructions thatwhen executed by data processing apparatus cause the data processingapparatus to perform operations including: receiving a second requestfor a second electronic map segment for a second geographic region thatincludes at least a portion of the first geographic entity, wherein thesecond request includes an identification of a second geographic entityidentified based on a search request for the second geographic entitysubmitted from a client device; retrieving, in response to the secondrequest for the second electronic map segment, a plurality of layers ofmap data associated with the second geographic region and data defininga boundary of the second geographic entity; rendering the secondelectronic map segment based on the retrieved plurality of layers of mapdata and the data defining the boundary of the second geographic entity,wherein one or more of the retrieved plurality of layers comprise arendering of a highlighted boundary of the second geographic entitywithout rendering a highlighted boundary of the first geographic entityidentified by the request; and transmitting the rendered secondelectronic map segment in response to the second request.
 19. Thecomputer storage medium of claim 13 wherein the rendering of thehighlighted boundary of the geographic entity represents a fuzzyboundary for the geographic entity.
 20. A system comprising: one or moremap request interpretation servers adapted to: receive, from a userdevice, a map request for an electronic map segment for a geographicregion, wherein the map request includes an identification of ageographic entity to be highlighted in the requested electronic mapsegment; and in response to receiving the request, retrieve a pluralityof layers of map data associated with the geographic region determinewhether the request includes an identification of a geographic entity tobe highlighted in the requested electronic map segment; and in responseto determining that the request includes an identification of ageographic entity to be highlighted in the requested electronic mapsegment, retrieve data defining a geographic boundary of the geographicentity, wherein the electronic map segment comprises a plurality of maptiles, and wherein a first subset of the map tiles include at least partof the geographic entity to be highlighted and a second subset of themap tiles do not include the geographic entity to be highlighted, atleast some of the second subset of map tiles being rendered beforereceiving the request from the client device; one or more map renderingservers adapted to render the first subset of the map tiles based on theretrieved plurality of layers of map data and the data defining thegeographic the boundary of the geographic entity, wherein the firstsubset of the map tiles rendered comprises a rendering of a highlightingof a geographic boundary of the geographic entity identified by therequest; and one or more map front end servers adapted to transmit therendered first subset of the map tiles.
 21. The system of claim 20further comprising one or more map search servers adapted to: receivethe map request; identify a geographic region associated with thegeographic entity in response to the map request; and generate theidentification of the geographic entity in response to the map request.22. The system of claim 21 wherein the one or more map search serversare further adapted to generate a uniform resource locator includingidentification of the geographic region and identification of thegeographic entity.
 23. The system of claim 20 further comprising a userdevice adapted to display the rendered electronic map segment.
 24. Thesystem of claim 23 wherein the user device is further adapted totransmit the map request to the map request interpretation server inresponse to receiving the uniform resource locator.
 25. The system ofclaim 24 wherein the user device is further adapted to initiate therequest.
 26. A method comprising: receiving a first search requestidentifying a first geographic entity associated with a first geographiclocation, wherein the first search request comprises one or moreparameters indicative of a desire to highlight a first geographic entityresponsive to the first search request; identifying, by one or moreprocessors, a geographic region comprising the first geographic locationassociated with the first geographic entity; identifying, by one or moreprocessors, a geographic map segment corresponding to the geographicregion comprising the first geographic location associated with thefirst geographic entity; identifying, by one or more processors, ageographic boundary of the first geographic entity; receiving, by theone or more processors, a first set of map tiles corresponding to thegeographic map segment, wherein one or more of the map tiles of thefirst set of map tiles comprise a representation of the boundary of thefirst geographic entity and one or more of the map tiles of the firstset of map tiles do not comprise a representation of the boundary of thefirst geographic entity; providing for display of the first set of maptiles corresponding to the map segment such that a geographic mapcomprising the geographic map segment corresponding to the geographicregion comprising the first geographic location associated with thefirst geographic entity and a highlighting of the geographic boundary ofthe first geographic entity is displayed; identifying, from the firstset of map tiles, a subset of map tiles that do not comprise arepresentation of the geographic boundary of the first geographicentity; and providing instructions that, when executed by a clientdevice from which the first search request was received, cause theclient device to store the subset of the map tiles in cache memory ofthe client device.
 27. The method of claim 26, further comprising:receiving a second search request identifying a second geographic entityassociated with a second geographic location, wherein the second searchrequest comprises one or more parameters indicative of a desire tohighlight a geographic entity responsive to the second search request;identifying, by one or more processors, a second geographic regioncomprising the second geographic location associated with the secondgeographic entity; identifying, by one or more processors, a secondgeographic map segment corresponding to the second geographic regioncomprising the second geographic location associated with the secondgeographic entity; identifying, by one or more processors, a secondboundary of the second geographic entity; identifying, by one or moreprocessors, a second set of map tiles corresponding to the secondgeographic map segment, wherein one or more of the second set of maptiles correspond to one or more of the map tiles of the subset of maptiles that (a) are stored in cache memory and (b) do not comprise arepresentation of the boundary of the geographic entity; and sending theclient device instructions that, when executed by the client device,cause the client device to perform operations comprising: retrieving,from cache memory, a first subset of map tiles that (a) correspond to amap tile of the second set of map tiles, (b) are stored in cache memoryand (c) do not comprise a representation of the boundary of thegeographic entity; generating a request for a second subset of map tilesthat (a) correspond to a map tile of the second set of map tiles, and(b) are not in the first subset of map tile retrieved from cache memory;receiving the second subset of the map tiles in response to the requestfor one or more map tiles, wherein at least some of the map tiles of thesecond subset of the map tiles received comprise a representation of thesecond boundary of the second geographic entity; and display of thefirst and second subsets of map tiles such that a second geographic mapcomprising the second geographic map segment corresponding to the secondgeographic region comprising the second geographic location associatedwith the second geographic entity and a highlighting of the secondboundary of the second geographic entity is displayed.